I am very sorry to tell you this, but your child will learn more from 1 on 1 interactions. So why not play some counting game with you child, and numerical games with them, such as baking a batch of cookies and counting the amount the amount on the tray, while also practicing adding and subtracting skills such as:
"If I ate 2 cookies then how many would be left or if I add another pan of cookies how many will we have altogether and show the child how to write the number down---hence also practicing handwriting skills which computers do not teach!!"
There is much more that a parent can do to prep their kids for school then turning on a computer to occupy their time and take responsibility for a parents job. Spending time with your kids offer precious moments and skills that may last a lifetime, turning on a computer just shifts the responsibility to a machine!